pub fn dp_rec_mc(mut amount: u32) -> u32 {
    let z = vec![1, 2, 5, 10, 20, 30, 50, 100];
    let mut res = 0;
    for i in z.iter().rev() {
        while amount >= *i {
            amount -= *i;
            res += 1;
        }
    }
    res
}
